1. Field of the Invention
The invention relates generally to rotary downhole tools and, more particularly, but not by way of limitation, it relates to a combination downhole tool which can be used for clean-out and subsequent fishing with a single entry into the hole.
2. Description of the Prior Art
The prior art includes numerous types of downhole tools used for both clean-out and various fishing operations and there have even been some prior attempts at combination-type tools. The U.S. Pat. No. 2,929,452 discloses a combination tool wherein the tool is attached to the rotary drill string and includes a lower shoe of cylindrical shape having an appropriate bottom cutting edge for clearing out around the fish and drill pipe at a designated depth. In addition, the clean-out tool includes a fishing tool within that consists of a tubular, small diameter drill rod that is slidably retained within the clean-out or washover cylinder. U.S. Pat. No. 2,830,663 discloses a permanent magnet fishing tool of a type wherein the tool includes a lower cutting ring for clearing out around the fish and for bringing an axially aligned permanent magnet into contact to retain the fish for drawing upward.
Yet another type of combination tool is shown in U.S. Pat. No. 2,090,616 wherein the lower, circular cutting edge of the tool coacts with a suction-type fishing tool. U.S. Pat. No. 1,968,282 is a form of fishing tool that also operates on the suction principle and it also includes a toothed foot or shoe which serves to cut around the fish and to position the fish for uptake.